Patch for ticket #138 - Added map picker to chose dive locations

For storing dive location, a map picker is added.

One could choose location of dive as well as time offset in minutes of the dive and store the information on server or locally as per preferences.

Changes made:
1. Added map picker option on add button in actionbar in HomeActivity.java.
2. The new strings are included in languages German, French, Russian and Romanian.
3. Changed if else ladder in HomeActivity.java to switch case for better code readability

Reported-by: henrik
Signed-off-by: Venkatesh Shukla <venkatesh.shukla.eee11@iitbhu.ac.in>